KR20050022648A - Method and apparatus for correcting sound field - Google Patents

Abstract

PURPOSE: A sound field calibration device and a method are provided to set an internal value having an output identical with an extracted detection signal, and to change the set value to have a sound field property identical with a pre-inputted target sound field, thereby calibrating a sound field. CONSTITUTION: A reproducer(100) reproduces an inputted electric signal as a sound. A remote controller(110) detects the reproduced sound, converts a detected signal into a wireless signal to wirelessly transmit the wireless signal, and remotely controls an audio device. A wireless receiver(120) receives the wireless signal to extract the detected signal. A sound field calibration signal processor(130) sets an internal value having an output identical with the detected signal, and changes the set value to have a sound field property identical with a pre-inputted target sound field to calibrate a sound field.

Description

Sound field correction apparatus and method {Method and apparatus for correcting sound field}

The present invention relates to a sound reproducing apparatus, and more particularly, to an apparatus and a method for performing sound field correction in an audio apparatus such as an audio portion of an audio system or a television system.

The sound reproduced by the audio device has a difference felt by the listener according to the sound field space in which the sound is propagated. Therefore, sound field correction is more important than listening to expensive parts of audio equipment to hear sound closer to the original sound.

5 is a graph comparing sound field characteristics of an anechoic room and a general listening room of a general audio device. The horizontal axis of the graph is the frequency of Herz-logarithmic and the vertical axis is the amplitude in decibels (dB). The upper frequency response 500 on the graph is measured in the anechoic chamber, and the lower frequency response 510 is measured in a general listening room.

In a typical listening room, the frequency response is relatively smooth. However, when measured in a general listening room, even if the same speaker, due to the influence of the room can see the frequency response characteristics in the form of a lot of dip (dip) and peak (peak) like the lower frequency response (510).

The cause of this phenomenon is a phenomenon in which a certain frequency band is reinforced or canceled by a room mode due to standing waves due to the shape of a listening room. This is especially true at low frequencies. The technique of correcting this to show a flat frequency response regardless of frequency is called sound field correction.

Conventionally, in order to correct the sound field of an audio device, the characteristics of the sound field space are determined by measuring the magnitude of the sound pressure reproduced in each channel, the distance from the source, and the frequency characteristics using a microphone connected by wire at a listening point in front of the speaker. After inputting the correction value of the measured sound field characteristics by using a separate device, the frequency distortion by the sound field was corrected by setting the gain value for each band to show the overall flat frequency characteristic.

However, in this case, it is troublesome to fix the microphone at the listening position because the wired microphone is used, and because the frequency characteristics of the speaker and the sound field are corrected using a method of adjusting the gain value for each band, the standing wave mode due to the room characteristics. There is a limit of sound field control that is difficult to remove effects such as comb filter effects and has a constant frequency characteristic.

In addition, since it is necessary to input the target sound field characteristics using a separate device, it is necessary to have expert knowledge about the separate equipment and sound field correction.

The technical problem to be achieved by the present invention is to provide a sound field correction apparatus and method capable of performing sound field correction without limiting the position of the microphone for sound field correction, and without the knowledge of a separate device and sound field correction.

According to a first aspect of the present invention, there is provided a sound field compensation device, comprising: a reproducing unit for reproducing an input electrical signal as a sound; A remote controller for detecting the reproduction sound, converting the detected signal into a wireless signal and transmitting the radio signal, and remotely controlling the audio device; A wireless receiver configured to receive the wirelessly transmitted wireless signal and extract the detection signal; And setting an internal value having an output that matches the extracted detection signal with respect to the electrical signal input to the reproducing unit, and correcting the sound field by changing the set value to have a sound field characteristic that matches the target sound field previously input. And a sound field correction signal processor.

The target sound field characteristic may be selected from a plurality of preset target sound field characteristics.

In addition, the sound field correction signal processor is characterized in that for correcting the sound field using the FIR adaptive filter.

In addition, preferably, further comprising an input signal generator for generating an electrical signal input to the reproduction unit.

In addition, preferably, the input electrical signal is one of a random noise signal or an impulse signal.

Preferably, the remote controller is a reproduction sound detector for detecting and converting the reproduction sound into an electrical signal, a wireless transmission unit for converting the detected electrical signal into a wireless signal for wireless transmission and a remote control unit for remotely controlling the audio device. It is characterized by including.

According to a second aspect of the present invention, there is provided a sound field correction method comprising: reproducing an electrical signal as sound; Detecting the reproduction sound, converting the detected signal into a wireless signal, and wirelessly transmitting the detected signal; Receiving the wirelessly transmitted wireless signal and extracting the detection signal; And setting an internal value of a sound field correcting device having an output that matches the extracted detection signal with respect to the reproduced electrical signal, and changing the setting value to have a sound field characteristic that matches a previously input target sound field. Characterized in that it comprises a step of correcting.

The target sound field characteristic may be selected from a plurality of preset target sound field characteristics.

Preferably, the sound field guaranteeing step is characterized by correcting the sound field by changing the coefficient value of the FIR adaptive filter.

In addition, preferably, further comprising the step of generating the input electrical signal.

Preferably, the reproduced electrical signal is one of a random noise signal or an impulse signal.

Preferably, the detecting of the reproduction sound, converting the detected signal into a wireless signal, and wirelessly transmitting the detected sound may be performed by a remote controller for remotely controlling the audio device.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a schematic block diagram of an embodiment of a sound field correction device according to the present invention. In FIG. 1, the playback unit 100 of the audio device is connected to the amplification unit 150 and the amplification unit 150 with the sound field correction signal processor 130, and the sound field correction signal processor 130 is an input signal generator and It is connected to the wireless receiver 120. The remote controller 110 is positioned between the playback unit 100 and the wireless receiver 120, and the playback sound detector 112 and the wireless transmitter 114 are connected to each other in the remote controller 110.

The input signal generator 140 generates an electrical signal input to the playback unit 100. For sound field correction, the input signal uses a lot of noise generators that generate white noise or pink noise. In this embodiment, a random noise generator or an impulse signal generator is used to have a full band frequency.

The playback unit 100 corresponds to a speaker and reproduces an input electrical signal as a sound and outputs the sound to the sound field space where the audio device is located.

The remote controller 110 includes a reproduction sound detector 112, a wireless transmitter 114, and a remote controller (not shown). The reproduction sound detector 112 detects an output reproduction sound and converts the generated reproduction sound into an electrical signal, and wirelessly transmits the signal. The unit 114 converts the converted electrical signal into a wireless signal for wireless transmission, and a remote controller (not shown) remotely controls the audio device.

 The wireless receiver 120 receives the wirelessly transmitted wireless signal and extracts the detection signal.

The sound field correction signal processor 130 is set by the internal value to have an output that is reproduced by the playback unit 100 and detected by the remote controller 110 and matched with the electrical signal received through the wireless receiver 120. The sound field is corrected by identifying the characteristic and changing an internal value set to match the characteristic of the identified sound field space with the characteristic of the target sound field input in advance.

The target sound field characteristics are set in advance. Unlike the general-purpose sound field correction apparatus, in a dedicated sound field correction apparatus for a specific audio apparatus, such as an audio section of a television, it is possible to predict the rough characteristics of the sound field to be reproduced. The sound field characteristics may be set to be selected by the user of the audio device from among the set sound field characteristics.

By setting a plurality of sound field characteristics in advance and selecting a target sound field characteristic suitable for the sound field space in which the audio device is located, the user does not need to use a separate sound field correction device, and also has expertise in sound field correction. Sound field correction can be performed without.

In addition, the preset target sound field may be set to allow the user of the audio device to select sound field characteristics that suit his or her taste. For example, the sound field characteristics having various sound field characteristics such as clear sound and bright sound may be preset. have.

In this embodiment, the sound field correction signal processor 130 corrects the sound field by using a finite impulse response (FIR) adaptive filter. By using the FIR adaptive filter, the possibility of sound quality deterioration is lower than in the case of using an infinite impulse response (IIR) filter having a nonlinear phase characteristic.

2 is a flowchart illustrating an embodiment of a sound field correction method according to the present invention. First, an electrical signal is generated (S200) and input to the playback unit 100 corresponding to the speaker, and the electrical signal input from the playback unit is reproduced as a sound and output to the sound field space (S210).

In the sound field correction, white noise or pink noise is often used. In the present invention, a random noise signal or an impulse signal is used to excite the acoustic system at the full band frequency.

The sound detected by the playback sound detector 112 corresponding to the microphone is converted into an electrical signal (S220), and the wireless transmitter 114 converts the sound into a wireless signal and wirelessly transmits it (S230). The method of wireless transmission may be implemented using various wireless transmission means such as radio frequency (RF), blue tooth, LED, and the like.

The process of detecting the reproduction sound, converting the detected signal into a wireless signal, and transmitting the wireless signal may be performed by a remote controller that remotely controls the audio device. In this case, the remote controller 110 includes a playback sound detector 112 and a wireless transmitter 114 in addition to the normal remote controller (not shown).

The detection signal is extracted by receiving the wirelessly transmitted wireless signal (S240), and an internal value of the sound field correction apparatus is set to have an output that matches the extracted detection signal. The setting of the internal value of the sound field correction device is performed by comparing the extracted detection signal with the internal value of the existing sound field correction device (S250), and changing the internal value (S260) if it does not match.

Since the sound field correction apparatus of this embodiment uses an adaptive filter, in particular, an FIR adaptive filter, changing the internal value corresponds to changing the coefficient of the FIR adaptive filter.

When the characteristics of the sound field space are grasped, that is, when the extracted detection signal and the output of the sound field compensating device match, the set value such that the sound field characteristics of the last determined pitch space have a sound field characteristic that matches the previously input target sound field. To correct the sound field.

This process is performed by comparing whether the output of the sound field correcting device that is already set coincides with a target sound field characteristic input in advance (S270), and changing the coefficient value of the FIR adaptive filter (S280) until it matches.

The target sound field characteristic is selected from a plurality of preset target sound field characteristics, and the effect thereof is as described above in the device invention.

In the present embodiment, the playback sound detector 112 and the wireless transmitter 114 are included in the remote controller 110. This configuration allows the user of the audio device to transmit a detection signal regardless of its position in the sound field space. It is possible to directly input the target sound field characteristic on the spot to correct the sound field characteristic.

As a result, the user of the audio device can easily perform sound field correction suitable for the position at any position in the sound field space.

FIG. 3 is a schematic block diagram of a process of the sound field correction signal processor of FIG. 1 to determine sound field characteristics of a sound field space. 3 is a diagram illustrating a system identification portion of a speaker and an acoustic system of the sound field correction method according to the present invention. The sound field 310 of FIG. 3 represents a system in which a speaker and a microphone are convolved, and includes a playback unit 100 and a playback sound detector of FIG. 1. First, a random noise or impulse signal is pulled in order to have an acoustic system, i.e., a sound field 310, at full-band frequency, and then an estimated signal d2 passing through the adaptive FIR filter at that time. The difference e1 is input to the Least Mean Square (LMS) algorithm to update the adaptive filter coefficients. By repeating this process, the adaptive filter coefficients can be approximated to the unit impulse response of the acoustic system.

4 is a schematic block diagram of a process in which the sound field correction signal processor of FIG. 1 performs sound field correction according to a target sound field characteristic. FIG. 4 illustrates an algorithm for correcting a sound field based on a target target sound field characteristic by using unit impulse responses of a speaker and a sound field of a listening room obtained from the system estimation of FIG. 3.

The input signal inputs a random noise signal to sufficiently excite the entire frequency band. The input signal outputs d3 by passing through a delay element 410 which serves to improve the convergence rate in a causal system and a target acoustic system having a target sound field characteristic 420 having a desired frequency response characteristic. The output value convolved with the initial adaptive FIR filter coefficients passes through the unit impulse response, which is an estimated sound field characteristic 440 representing the speaker and sound field obtained from the system estimation block, and outputs d4. At this time, the process of minimizing the difference e2 between d3 and d4 is repeated to obtain an optimal adaptive filter 430 coefficient value. This process also uses the LMS algorithm.

6 is a view comparing sound field characteristics before and after sound field correction according to an exemplary embodiment of the present invention with respect to target sound field characteristics in a general listening room. In FIG. 6, the flattest curve 600 corresponds to the target sound field characteristic, the most variable curve 620 is the frequency response curve before sound field correction, and the flatness curve 610 is the sound field correction according to the present invention. The following is the frequency response characteristic.

In FIG. 6, the sound field characteristic, that is, the frequency response, after the correction is much closer to the target sound field characteristic after the sound field correction.

According to the present invention, a user of an audio device can perform sound field correction without a separate device or expertise for sound field correction, and can conveniently perform sound field correction anywhere in the sound field space regardless of the user's position. do.

1 is a schematic block diagram of an embodiment of a sound field correction device according to the present invention.

2 is a flowchart illustrating an embodiment of a sound field correction method according to the present invention.

FIG. 3 is a schematic block diagram of a process in which the sound field correction signal processor of FIG. 1 detects sound field characteristics of a sound field space.

4 is a schematic block diagram of a process in which the sound field correction signal processor of FIG. 1 performs sound field correction according to a target sound field characteristic.

 5 is a graph comparing sound field characteristics of an anechoic room and a general listening room of a general audio device.

6 is a graph comparing sound field characteristics before and after sound field correction according to an exemplary embodiment of the present invention with respect to target sound field characteristics in a general listening room.

Claims (12)

In an audio device, Reproducing unit for reproducing the input electrical signal as a sound; A remote controller for detecting the reproduction sound, converting the detected signal into a wireless signal and transmitting the radio signal, and remotely controlling the audio device; A wireless receiver configured to receive the wirelessly transmitted wireless signal and extract the detection signal; And A sound field that sets an internal value having an output that matches the extracted detection signal with respect to the electrical signal input to the reproduction unit, and corrects the sound field by changing the set value to have a sound field characteristic that matches the target sound field previously input. Sound field correction apparatus comprising a correction signal processing unit. The sound field correcting apparatus of claim 1, wherein the target sound field characteristic is selected from a plurality of preset target sound field characteristics. The sound field correcting apparatus of claim 1, wherein the sound field correction signal processor corrects a sound field by using an FIR adaptive filter. The sound field correcting apparatus of claim 1, further comprising an input signal generator configured to generate an electrical signal input to the reproduction unit. The sound field correcting apparatus of claim 1 or 4, wherein the input electrical signal is one of a random noise signal or an impulse signal. The apparatus of claim 1, wherein the remote controller detects the reproduced sound and converts the reproduced sound into an electrical signal, a wireless transmitter converting the detected electrical signal into a wireless signal, and wirelessly transmits the remote control. Sound field correction apparatus comprising a. Reproducing the electrical signal as a sound; Detecting the reproduction sound, converting the detected signal into a wireless signal, and wirelessly transmitting the detected signal; Receiving the wirelessly transmitted wireless signal and extracting the detection signal; And The internal value of the sound field correcting device having an output that matches the extracted detection signal is set for the reproduced electric signal, and the sound field is corrected by changing the set value to have a sound field characteristic that matches the previously input target sound field. Sound field correction method comprising the step of. 8. The sound field correction method of claim 7, wherein the target sound field characteristic is selected from a plurality of preset target sound field characteristics. 8. The sound field correction method according to claim 7, wherein the sound field guaranteeing step corrects the sound field by changing a coefficient value of the FIR adaptive filter. 8. The sound field correction method of claim 7, further comprising generating the input electrical signal. The sound field correction method according to claim 7 or 10, wherein the reproduced electrical signal is one of a random noise signal or an impulse signal. The method of claim 7, wherein the detecting of the reproduction sound, converting the detected signal into a wireless signal, and wirelessly transmitting the detected sound is performed by a remote controller that remotely controls the audio device.